1、Designation: D 1414 94 (Reapproved 2008)Standard Test Methods forRubber O-Rings1This standard is issued under the fixed designation D 1414; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in pare
2、ntheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 These test methods describe the procedures for deter-mining the phys
3、ical properties of O-rings and changes in theseproperties due to aging.1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use
4、. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 297 Test Methods for Rubber ProductsChemicalAnalysisD 395 Test Methods for
5、 Rubber PropertyCompressionSetD 412 Test Methods for Vulcanized Rubber and Thermo-plastic ElastomersTensionD 471 Test Method for Rubber PropertyEffect of LiquidsD 573 Test Method for RubberDeterioration in an AirOvenD 865 Test Method for RubberDeterioration by Heatingin Air (Test Tube Enclosure)D 13
6、29 Test Method for Evaluating Rubber PropertyRetraction at Lower Temperatures (TR Test)D 1415 Test Method for Rubber PropertyInternationalHardnessD 2240 Test Method for Rubber PropertyDurometerHardnessD 4483 Practice for Evaluating Precision for Test MethodStandards in the Rubber and Carbon Black Ma
7、nufacturingIndustriesE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 Aerospace Standard:AS568A Oring Sizes33. Terminology3.1 Definitions:3.1.1 O-ringa rubber seal of homogeneous compositionmolded in one piece to the configuration of a torus with c
8、ircularcross section. The O-ring is used as a dynamic or static sealusually installed in a machined groove.4. Significance and Use4.1 These test methods provide acceptable procedures forquality control purposes and for the determination of engineer-ing characteristics.5. General Methods5.1 Except as
9、 otherwise specified in these test methods forrubber O-rings, the followingASTM test methods applicable ingeneral to vulcanized rubber, shall be complied with asrequired and are hereby made a part of these test methods:5.1.1 Tension TestTest Methods D 412.5.1.2 Compression SetTest Methods D 395.5.1.
10、3 Low TemperatureTest Method D 1329.5.1.4 DensityTest Methods D 297.5.1.5 Fluid AgingTest Method D 471.5.1.6 Heat AgingTest Methods D 865 and D 573.5.1.7 HardnessTest Methods D 2240 and D 1415.5.2 In case of conflict between the provisions of these testmethods and those of detailed procedures herein
11、, the lattershall take precedence.6. Test Conditions6.1 The temperature of the testing room shall be 23 6 2C(73.4 6 3.6F). The specimens to be tested shall be kept in thisroom for a minimum of 30 min previous to the time of testing.For referee tests the minimum time for conditioning shall be 16h. In
12、 cases where this temperature cannot be obtained, theactual temperature shall be reported.1These test methods are under the jurisdiction of ASTM Committee D11 onRubber and are the direct responsibility of Subcommittee D11.36 on Seals.Current edition approved May 1, 2008. Published June 2008. Origina
13、llyapproved in 1956. Last previous edition approved in 2003 as D 1414 94 (2003).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page
14、onthe ASTM website.3Standardization Documents Order Desk, Bldg. 4 Section D, 700 Robbins Ave.,Philadelphia, PA 19111-5094, Attn: NPODS.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7. Dimensional Measurements7.1 Thickness:7.1.1 The
15、 thickness or cross section may be measured byone of the following methods: (a) a hand micrometer equippedwith 6-mm (0.25-in.) diameter hemispherical tips (ballpoint ortubing micrometers), (b) dial indicators that have a maximumcontact force of 0.29 N (29 gf), or (c) an electronic micrometerwith a s
16、pring force of 0.1 N (10 gf) maximum. Better accuracycan be obtained with a 0.05-N (5-gf) spring or with no spring.In case of referee tests, both laboratories shall use the samespring force.7.1.2 The O-ring specimen shall be measured at four pointsequally distributed around the circumference in both
17、 the radialand axial direction. An average reading shall be used forcalculation.7.2 DiameterA stepped cone or optical comparator maybe used for measuring the inside diameter of small rings. Thediametric intervals of the stepped cone shall not exceed 2 % ofthe diameter to be measured (see Fig. 1).8.
18、Tension Testing8.1 Testing Machine The testing machine shall conformto the requirements specified in Section 3 of Test MethodsD 412, with the exception of the grips. Grips for testing ringsshall consist of ball-bearing spools at least 9 mm (0.35 in.) indiameter, and be capable of being brought withi
19、n 19 mm (0.75in.) center-to-center distance at closest approach. Stresseswithin the specimen shall be minimized by (1) rotating onespool one full revolution for each 150 mm (6.0 in.) of travel ofthe power-driven grips or (2) lubricating the contact surface ofthe spools with castor oil. Grips for tes
20、ting straight specimensmay be of any type provided breaks do not occur in a portionof the specimen that has been at any time in contact with thegrips. For specimens smaller than 25 mm (1 in.) in insidediameter, spools of smaller diameter and closer approach maybe employed.8.2 Test Specimen:8.2.1 The
21、 test specimen shall consist of an entire O-ringexcept in the following cases: (1) when the diameter is toolarge to permit a break within the limits of travel of the testingmachine, (2) when the specimen has been previously cut opento permit an aging test, and (3) when the specimen is unagedbut is t
22、o be compared with an aged specimen as described in(2). For these cases a specimen cut from a ring shall beemployed.8.2.2 Specimens that exhibit obvious flaws at any point onthe surface, such as might result from imperfect molding orflash removal, shall not be tested.8.3 Procedure for Determination
23、of Tensile Strength, Ulti-mate Elongation, and Tensile Stress:8.3.1 Bring the grips close enough together so the specimencan be installed without stretching. Set the machine for a speedof 500 6 50 mm (20 6 2 in.)/min, set the chart recorder, andengage the clutch. (If a recorder is not used, note the
24、 spoolcenter-to-center distance continually by means of a suitablescale). The stressed inside circumference, L, is equal to twicethe distance between spools plus the circumference of onespool. Record the breaking force value, F, at the elongationspecified for tensile stress and at the time of ruptur
25、e. Measurethe center-to-center distance between the spools at rupture tothe nearest 2.5 mm (0.1 in.) and record as the value for D.8.3.2 For the application of bench marks to segmentedspecimens as described in 8.2, hold the piece as straight aspossible being careful not to apply excessive stress. Fo
26、llow theprocedure described in 8.3.1. Discard results for any specimenthat breaks at a point that has at any time contacted the grip,and test an additional specimen. A suitable extensiometer maybe employed for elongation determination.8.4 Calculations:8.4.1 Tensile Strength Calculate the tensile str
27、ength asfollows:8.4.1.1 For O-rings on spool grips:T 5 F/A (1)where:T = tensile strength,F = breaking force, andA = twice the cross-sectional area calculated from axialthickness, W, as follows:A 5pW2/2 5 1.57 W2(2)therefore:T 5 F/1.57 W2(3)8.4.1.2 For straight or single-strand specimens:FIG. 1 Stepp
28、ed Cone GageD 1414 94 (2008)2A 5 0.785 W2(4)T 5 F/0.785 W2(5)8.4.2 Ultimate ElongationCalculate the ultimate elonga-tion as follows:8.4.2.1 For rings:Ultimate elongation, % 5 2D 1 G 2 C!/C 3 100 (6)where:D = distance between centers of the spool grips at the timeof rupture of specimen,G = circumfere
29、nce of one spool (spool diameter 3 3.14),andC = inside circumference of the specimen (or inside diam-eter 3 3.14).8.4.2.2 For straight or single-strand specimen cut from anO-ring:Ultimate elongation, % 5 L 2 Lo!/Lo# 3 100 (7)where:L = observed distance between bench marks of stressedspecimen, andLo=
30、 original distance between bench marks.8.4.3 Tensile Stress Calculate the tensile stress as in thecase of tensile strength except the stress is reported at apredetermined elongation below the ultimate elongation. Cal-culate the center-to-center distance of the spool grips, D, wherethe prescribed elo
31、ngation, E, occurs, as follows:D 5 1/2EC/100! 1 C 2 G (8)NOTE 1This value of tensile stress at a predetermined elongation isbased upon inside circumference and differs from that determined by TestMethods D 412, which is based on the mean circumference.8.5 Characteristics of Sample TestedThe median o
32、f thevalues for three specimens shall be taken as the characteristicsof the sample tested, except that under the following conditionsthe median of the values for five specimens (two additional)shall be used:8.5.1 If one or more values do not meet the specifiedrequirements when testing for compliance
33、 with specifications.8.5.2 If referee tests are being made.8.6 Report:8.6.1 The report shall include the following:8.6.1.1 Results calculated as in 8.4,8.6.1.2 Date of test,8.6.1.3 Temperature of test room if other than provided forin Section 6,8.6.1.4 Type of testing machine used, including diamete
34、r ofspool grip if other than standard, and speed, if other than 8.360.8 mm (20.0 6 2 in.)/min, and8.6.1.5 Type of specimen (ring or straight).9. Tension Set Test9.1 Procedure:9.1.1 Stretch the O-ring specimens to 100 % elongation andhold at this strain for 10 min. At the end of this period releaseth
35、e specimen and allow it to recover for 10 min. At the end ofthis recovery period, measure the inside diameter with a stepgage reference in 7.2 and shown in Fig. 1.9.1.2 Apply the strain by (1) stretching the specimen over atapered cone which has a step at the required 100 % elongation,or (2) by mean
36、s of a tension test machine stopping the machineat 100 % elongation, or ( 3) by the use of any special fixturecapable of holding the O-ring over two spools at constantdistance between spool centers.9.2 Calculation Calculate tension set as follows:Tension set, % 5 L12 Lo!/Lo# 3 100 (9)where:L1= diame
37、ter after testing, andLo= original diameter.9.3 Straight specimens cut from large O-rings may be testedand calculated in accordance with Test Methods D 412.10. Compression Set Test10.1 Nature of Test The compression set of O-ring speci-mens shall follow the general procedures of Method B of TestMeth
38、ods D 395, with the following exceptions:10.2 Apparatus:10.2.1 SpacersThe spacers shall be adjusted to within0.025 mm (0.01 in.). This can be done by employing shimstock of various thickness.10.2.2 Measurement The cross section before and aftertest shall be measured in the same marked location with
39、aball-point (tubing) micrometer or other method as described in7.1.10.3 Test Specimen The specimen shall be a suitablesection cut from the sample O-ring.A52-mm (2-in.) section hasbeen found to be satisfactory on sample O-rings of 17-mm(0.67-in.) or larger inside diameter. On smaller O-rings, asectio
40、n of approximately 3 mm (18 in.) shall be cut from thesample and discarded.NOTE 2Testing a whole O-ring for compression set is always avoidedbecause air trapped inside the O-ring results in a different set of conditionson the inside and outside surface of the specimen.10.4 ProcedureMeasure the actua
41、l specimen to within0.025 mm (0.001 in.) and calculate the spacer to be 75 % ofthis thickness, to within 0.025 mm (0.001 in.). Close the plates,employing a sufficient number of bolts to prevent deflectionupon heating. At the end of the heating period, release theplates as soon as possible and allow
42、the specimens to cool toroom temperature under the conditions described in TestMethods D 395.11. Compression Set in Liquids11.1 Compression set may be conducted immersed in anyliquid provided a suitable container is available. The containerneeds to be large enough to hold the plates and withstand th
43、evapor pressure of the liquid at test temperature.11.2 The specimen is prepared in accordance with 10.3, andat the termination of the heating period the plates are releasedimmediately and the specimens are allowed to cool to roomD 1414 94 (2008)3temperature for 30 min in a fresh cool portion of the
44、test liquid.Measurement and reporting are the same except the type ofliquid is listed in the report.12. Low-Temperature Test12.1 Nature of Test The TR-10 or Temperature RetractionTest shall be in accordance with Test Method D 1329 with theexceptions given in 12.2 to 12.4.12.2 Test Specimen The test
45、specimen shall be an O-ringof 1.5 to 3.8-mm (0.06 to 0.15-in.) cross-sectional diameter andof sufficient length to reach from clamp to clamp when the ringis cut and held in straight position.12.3 ProcedureStretch the mounted specimen 50 % asstandard. If a greater or lesser stretch is used, report th
46、e actualstretch.12.4 ReportThe report shall include the following:12.4.1 Testing elongation, in percent, and12.4.2 Temperature at which the specimen retracts 10 %,designated as TR-10 and at other points, such as 30, 50, or70 %, or all, if required.13. Relative Density Test13.1 Test SpecimenAny O-rin
47、g, O-rings, or segment of anO-ring may be considered as the specimen. The minimum massof the specimen shall be 0.005 N (0.5 gf). In the case of verysmall O-rings, two or more pieces may be used as the specimento accomplish this total minimum mass.13.2 ProcedureEmploy the procedure outlined in TestMe
48、thods D 297, density hydrostatic method.NOTE 3Extreme accuracy is required in making relative densitydeterminations on small O-rings 0.001 N (1 g or less). The surface tensionon the suspending wire is critical; this wire should be of the smallestdiameter corrosion-resistant wire that will support th
49、e specimen weight.This surface tension on the wire and the elimination of small air bubbleson the surface of the specimen can be reduced by the addition of a fewdrops of wetting agent to the water in the weighing beaker.14. Immersion Test14.1 Nature of Test For determination of the changes inphysical properties after liquid immersion, the definitions,standard test liquid descriptions, and general technique shall bein accordance with Test Method D 471. The detailed procedurefor O-rings, outlined in this section however, shall tak
